ABSTRACT
BACKGROUND: Leishmaniasis is a parasitic disease induced by a protozoan from the genus Leishmania. No effective vaccine has yet been developed against the disease. AIM: In this work, two nano-vaccines, TSA recombinant plasmid and dendrimer and poly (methyl methacrylate) (PMMA) nanoparticles (as adjuvants), were designed and tested for their immunogenicity in BALB/c mice. METHODS: After the plasmid construction and preparation of adjuvants, three intramuscular injections of the nano-vaccines (100 µg) and the recombinant TSA protein (20 µg) were subcutaneously performed. Eventually, the challenged animals were infected with the parasites (1*106 promastigotes). After the last injections of the nano-vaccines, the responses of their antibody subclasses and cytokines were assessed via ELISA method before and after the challenge. RESULTS: This study revealed that the new nano-vaccines were strong and effective in inducing specific antibody and cellular responses and reducing the parasite burden in the spleen compared to the control groups of Leishmania major-infected BALB/c mice. CONCLUSION: Based on the results, we can suggest that the formulated vaccines are suitable candidates for further studies in the field of leishmaniasis control.
ABSTRACT
Leishmaniasis is a parasitic disease caused by several species of the genus Leishmania. Montanide ISA 70 is an adjuvant composed of a natural metabolizable oil and a very refined emulsifier from the manide monooleate family. The TSA (thiol-specific antioxidant) is a important antigen of Leishmania major. The purpose of this work was protein-vaccine efficacy as an protection and excellent candidate in the presence Montanide. The expression of recombinant protein was confirmed with SDS (sodium dodecyl sulfate) page and Western bloting. 48 BALB/c mice were divided into four groups (TSA/Freund,TSA/Alum + BCG, TSA/Montanide and PBS groups) and immunized with 20 µg of vaccine subcutaneously three times intervals on days 0, 14 and 28. The mice were challenged with parasite 21 days after final immunization. The lymphocyte proliferation was evaluated with Brdu method. Cytokines and also total antibody and subclasses were evaluated with ELISA method. The vaccine formulated with the recombinant TSA protein with Montanide induced lymphocytes proliferation cytokines and total antibody and subclasses as compared with the control group.
ABSTRACT
Leishmaniasis is a major infectious disease caused by protozoan parasites of the genus Leishmania. Despite of many efforts toward vaccine against Leishmania no effective vaccine has been approved yet. DNA vaccines can generate more powerful and broad immune responses than conventional vaccines. In order to increase immunity, the DNA vaccine has been supplemented with adjuvant. In this study a new nano-vaccine containing TSA recombinant plasmid and poly(methylmethacrylate) nanoparticles (act as adjuvant) was designed and its immunogenicity tested on BALB/c mouse. After three intramuscular injection of nano-vaccine (100 µg), the recombinant TSA protein (20 µg) was injected subcutaneously. Finally as a challenge animals were infected by Leishmania major. After the last injection of nano-vaccine, after protein booster injection, and also after challenge, cellular immune and antibody responses were evaluated by ELISA method. The findings of this study showed the new nano-vaccine was capable of induction both cytokines secretion and specific antibody responses, but predominant Th1 immune response characterized by IFN-γ production compared to control groups. Moreover, results revealed that nano-vaccine was effective in reducing parasite burden in the spleen of Leishmania major-infected BALB/c mice. Base on results, current candidate vaccine has potency for further studies.